In Vivo vs. In Vitro

So, many people are no longer aware of this, but there are basically two types of observation which may be made in science: ‘in vitro’ and ‘in vivo’.

‘In vitro’ is Latin for ‘in the glass’, and originally referred to reactions observed in cultures in a Petri dish. However, by extension, it refers to observations of an artificially-controlled environment. ‘In vivo’, on the other hand, is Latin for ‘in life’–originally, reactions observed in a living body; by extension, to observations of real-world (i.e., non-controlled) phenomena.

In vivo always trumps in vitro. If it only happens in the Petri dish, it isn’t a valid observation.

Now, look at your climate-modeling software (video games).

Global temperatures rise catastrophically in response to CO2.

Now look at the real world world.

Global temperatures stay flat for 20 years, despite large increase in CO2.